Datasheet

Thermal Specifications
88
bits 3:1 of the same IA32_CLOCK_MODULATION MSR. In On-Demand mode, the duty
cycle can be programmed from 12.5% on/ 87.5% off to 87.5% on/12.5% off in 12.5%
increments. On-Demand mode may be used in conjunction with the Thermal Monitor;
however, if the system tries to enable On-Demand mode at the same time the TCC is
engaged, the factory configured duty cycle of the TCC will override the duty cycle
selected by the On-Demand mode.
6.2.3 PROCHOT# Signal
An external signal, PROCHOT# (processor hot) is asserted when the processor die
temperature of any processor cores reaches its factory configured trip point. If Thermal
Monitor is enabled (note that Thermal Monitor must be enabled for the processor to be
operating within specification), the TCC will be active when PROCHOT# is asserted. The
processor can be configured to generate an interrupt upon the assertion or de-
assertion of PROCHOT#. Refer to the Intel® 64 and IA-32 Architectures Software
Developer’s Manual for specific register and programming details.
PROCHOT# is designed to assert at or a few degrees higher than maximum T
CASE
when
dissipating TDP power, and cannot be interpreted as an indication of processor case
temperature. This temperature delta accounts for processor package, lifetime and
manufacturing variations and attempts to ensure the Thermal Control Circuit is not
activated below maximum T
CASE
when dissipating TDP power. There is no defined or
fixed correlation between the PROCHOT# trip temperature, or the case temperature.
Thermal solutions must be designed to the processor specifications and cannot be
adjusted based on experimental measurements of T
CASE
, or PROCHOT#.
6.2.4 FORCEPR# Signal
The FORCEPR# (force power reduction) input can be used by the platform to cause the
Dual-Core Intel® Xeon® Processor 5200 Series to activate the TCC. If the Thermal
Monitor is enabled, the TCC will be activated upon the assertion of the FORCEPR#
signal. Assertion of the FORCEPR# signal will activate TCC for all processor cores. The
TCC will remain active until the system deasserts FORCEPR#. FORCEPR# is an
asynchronous input. FORCEPR# can be used to thermally protect other system
components. To use the VR as an example, when FORCEPR# is asserted, the TCC
circuit in the processor will activate, reducing the current consumption of the processor
and the corresponding temperature of the VR.
It should be noted that assertion of FORCEPR# does not automatically assert
PROCHOT#. As mentioned previously, the PROCHOT# signal is asserted when a high
temperature situation is detected. A minimum pulse width of 500 µs is recommended
when FORCEPR# is asserted by the system. Sustained activation of the FORCEPR#
signal may cause noticeable platform performance degradation.
Refer to the appropriate platform design guidelines for details on implementing the
FORCEPR# signal feature.
6.2.5 THERMTRIP# Signal
Regardless of whether or not Intel® Thermal Monitor 1 or Intel® Thermal Monitor 2 is
enabled, in the event of a catastrophic cooling failure, the processor will automatically
shut down when the silicon has reached an elevated temperature (refer to the
THERMTRIP# definition in Table 5-1). At this point, the FSB signal THERMTRIP# will go
active and stay active as described in Table 5-1. THERMTRIP# activation is independent
of processor activity and does not generate any bus cycles. Intel also recommends the
removal of V
TT
.